Device for testing the accuracy of a time delay relay including means for measuring the elapsed times of the relay&#39;s closed and open cycles



Feb. 15, 1966 s. A. HENDERSON 3,235,794

DEVICE FOR TESTING THE ACCURACY OF A TIME DELAY RELAY INCLUDING MEANS FOR MEASURING THE ELAPSED TIMES OF THE RELAYS CLOSED AND OPEN CYCLES Filed Feb. 11, 1959 r/ THEE/7077C [7/ 79 i PUMP I l mmMor/c l I I I c FHA) I i 76 I l wfw orrze ga United States Patent Ofifice 3,235,794 Patented Feb. 15, 1966 DEVICE FOR TESTING THE ACCURACY OF A TIME DELAY RELAY INCLUDING MEANS FOR MEASURING THE ELAPSED TEMES OF THE RE- LAYS CLOSED AND @PEN CYCLES Stanford A. Henderson, Snyder, N.Y., assignor to Gornco Surgical Manufacturing Corp, Bufialo, N.Y., a corporation of New York Filed Feb. 11, 1959, Ser. No. 792,676 18 Claims. (Cl. 324-28) This invention relates to a device for testing the accuracy of a time delay relay, and more particularly to a device for measuring the elapsed times of the closed and open cycles of a time delay relay of the recycling thermal type, more commonly known as a thermostat.

The invention is especially adapted for testing the accuracy of a thermostat incorporated in an intermittently operating pump such as the thermotic pump described in United States Letters Patent 2,346,841 and 2,465,865. Such a thermotic pump is useful for effecting drainage of fluid from the human body. In such operation, it is necessary that the pump have a low suction value, as well as on and off periods or cycles of short duration, thereby to effect a gentle drainage and to release the flesh drawn against the catheter tube following each suction cycle, so as to render the catheter operative for drainage during the next suction cycle. It is likewise necessary that the on and oif cycles be constant in duration and uniformly repeated in order to avoid undue strain on the body part being drained, as well as to provide for efiicient and effective operation of the pump.

As disclosed in the aforesaid patents, such a thermotic pump is intermittently actuated by the expansion and contraction air caused by the application and withdrawal of heat. To this end, the pump is provided with a working chamber containing a resistance heating wire or filament and a check valve connected to the chamber. During the on or dwell cycle of the pump (no suction), the filament is energized to heat and expand the air in the chamber, the valve permitting this air to exhaust from the chamber to the atmosphere and create a partial vacuum in the chamber. During the off or suction cycle of the pump, the filament is de-energized to cool whatever air remains in the chamber, and the valve permits additional cool air to enter the chamber.

In order to rapidly heat and cool the filament at regular intervals, a thermostat, often called a thermotic relay, is incorporated in the pump, the thermostat having closed and open cycles corresponding to and controlling the on and off cycles respectively, of the pump. Basically, the thermostat is composed of an oscillatable bi-metallic strip, loosely surrounded by a resistance wire, and normally biased to close an adjacent push-button switch, thereby completing the circuit to the filament in the working chamber of the pump, for the on cycle. As the resistance wire is heated, the bi-metallic strip is biased to open the switch for the off cycle. To vary the oscillation of the bi-metallic strip for opening and closing the switch, the strip is provided with an adjustable switch contact screw, and sometimes a variable resistance is employed for the same purpose, either or both adjustments changing the on and off cycles of the pump.

After repeated usage, or even before usage and installation of the thermostat in the pump, one or the other, or possibly both of these adjusting devices may become out of proper adjustment, thereby varying the on" and/or off cycles from those desired. This may result in a substantial reduction in the effectiveness and efliciency of the pump, as well as in damage to its working parts, making costly repairs necessary. For example, if the on cycle becomes too long, the filament in the working chamber will overheat and eventually rupture, thereby breaking the necessary electrical circuit and rendering the pump inoperative; likewise, the bi-metallic strip will burn and change its time constant, thereby aggravating the undesirable cyclic variations. On the other hand, if the off cycle is too long, the pump will not develop a sufficient amount of suction or pressure for effective and efiicient operation.

Accordingly, it is a primary object of this invention to provide a device for testing the accuracy of a time delay relay such as a thermostat, either as a separate unit or when assembled with the apparatus which it controls, such as a thermotic pump, and thereby prevent or at least minimize the undesirable consequences resulting from cyclic variations in the operation of the apparatus, such as those described above.

Another object of the invention is to provide a device for measuring the elapsed times of the closed and open cycles of a time delay relay such as a thermostat, which cycles correspond to and control the on and 01f cycles of its associated apparatus, such as a thermotic pump.

A further object of the invention is to provide such a testing device which is elficient, accurate and automatic in operation, as well as simple and compact in construction; which can be easily connected to a time delay relay; which facilitates recording of its indicated measurements, and which can be left unattended in operation without damaging its measuring components.

Additional objects and advantages of the invention will become apparent upon consideration of the following detailed description and appended claims in conjunction with the accompanying drawing, wherein:

FIG. 1 is a schematic view illustrating in diagrammatic form, an assembly of a thermotic pump and its thermostat, together with the electrical controls and the measuring components constituting a preferred embodiment of the invention, and

FIG. 2 is a partial perspective view of the measuring lccimponents which are diagrammatically illustrated in Referring to FIG. 1, the assembly of intermittently operating thermotic pump 10 and its controlling thermostat 11 is illustrated diagrammatically as connected to a single source of alternating current S. The remainder of the figure constitutes the thermostat testing device 12 embodying the invention, and which is connected between source S and the assembly of pump 10 and thermostat 11.

Basically, testing device 12 is composed of identical, motor-driven clock mechanisms 13 and 14 for measuring the closed and open cycles respectively of thermostat 11; a separate circuit for actuating and tie-actuating each of mechanisms 13 and 14; a single pole, double throw magnetic relay 15 for sequentially actuating and de-actuating mechanisms 13 and 14 by closing and opening their circuits respectively; a double pole, single throw, magnetic relay 16 which is energizable for simultaneously closing the circuit for mechanism 14 and energizing relay 15, and reenergizable for opening said circuit and preventing energization of relay 15; a manual push button switch 17 for independently stepping relays 15 and 16 or 16 alone; terminals T for testing thermostat 11 as a separate unit; a single pole, single throw magnetic relay 18 for en ergizing and re-energizing relay 16, as well as for deenergizing relay 15, and a rectifying control circuit 19 for energizing and de-energizing relay 18, circuit 19 being sequentially energized and de-energized by thermostat 11 in response to its closed and open cycles respectively.

Referring to FIG. 2, the details of each mechanism 13 and 14 are identical, therefore a description of 13 will suffice for both, the corresponding parts of 14 being indicated by the same numerals, primed. This mechanism includes a synchronous motor 20 having a shaft 21 for driving a differential 22. A clutch 23 operated by solenoid 24 is engageable with differential 22 for driving shaft 25 and rotating indicator 26 thereon relative to a fixed dial 27 for measuring the elapsed time of the closed cycle of thermostat 11. In order to prevent indicator 26 from attempting to rotate beyond the limits of dial 27, shaft 25 is provided with a disc 28 having a projecting lug 29 engageable with a limit switch 30. Thus, when pointer 26 has rotated to the upper limit of dial 27, lug 29 will engage and open switch 30, which in turn will de-energize solenoid 24 to disengage clutch 23 from differential 22, thereby automatically stopping further rotation of indicator 26, and preventing damage to the mechanism.

In order to reset indicator 26, a coil spring 31 is attached at its inner end to shaft 25 and at its outer end to the body of mechanism 13. Thus, when shaft 25 is driven, spring 31 is Wound up, to automatically unwind and return indicator 26 to its zero or starting position at the lower limit of dial 27. However, spring 31 is normally prevented from resetting indicator 26 by a manually releasable brake 32, which is composed of a push rod 33 and a transverse arm 34 provided at one end with a lining 35 normally biased into contact with the underside of disc 28 by compression spring 35a. The friction between brake lining 35 and disc 28 is sufiicient to prevent unwinding of self-actuating spring 31 when shaft 25 is not driven by differential 22, but like spring 31, does not offer sufficient resistance to interfere with rotation of shaft 25 by differential 22, or affect the accuracy of indicator 26.

Obviously, mechanism 14 operates in exactly the same manner. While a separate brake could be employed for each of mechanisms 13 and 14, it is preferred for convenience and simplicity that single brake 32 be releasable from both discs 28 and 28' for simultaneously resetting indicators 26 and 26. For this purpose, brake arm 34 is provided at its other end with lining 35.

Referring back to FIG. 1, the circuit for mechanism 13 includes solenoid operated clutch 23, limit switch 30 and relay 15, while the circuit for mechanism 14 includes solenoid operated clutch 23, limit switch 30', relay 16 and relay 15. The latter includes a solenoid 36, which upon energization throws pole 37 from contact 38 to contact 39 for simultaneously opening the circuit for deactuating mechanism 14 and closing the circuit for actuating mechanism 13. Upon de-ener gization of solenoid 36, pole 37 is thrown back to the position illustrated by a spring (not shown), thereby simultaneously closing the circuit for actuating mechanism 14 and opening the circuit for de-actuating mechanism 13.

Relay 16 includes solenoid 40, cam 41, lower pole 42 and its contact 43 and upper pole 44 and its contact 45. Upon energization of solenoid 40, cam 41 is rotated 90 degrees from the position shown to throw poles 42 and 44 to their respective contacts 43 and 45, thereby simultaneously closing the circuit for actuating mechanism 14 and energizing relay 15, which immediately opens the aforesaid circuit and closes the circuit for actuating mechanism 13. Upon de-energization of solenoid 40, cam 41 does not rotate, thereby leaving relay 16 in its previously energized condition. However, relay is now de-energized, its de-energized solenoid ,36 allowing its spring-biased pole 37 to be thrown back to contact 38, thereby completing the circuit for actuating mechanism 14 through previously closed pole 44 and contact 45 in relay 16. Upon the following energization of solenoid 40, relay 16 is re-energized, whereupon cam 41 is rotated 90 degrees to permit the spring (not shown) biased poles 42 and 44 to be thrown to the open position, as shown. Thus the circuit for actuating mechanism 14 is opened and relay 15 is prevented from being energized.

Push button switch 17 is provided for stepping relays 15 and 16 or 16 alone, as will be explained more in detail below. Terminals T are provided for bypassing relay 18 and rectifying control circuit 19 in order to make a direct connection to thermostat 11. These terminals are employed when it is desired to test thermostat 11 as a separate unit, there being no need for relay 18 and circuit 19.

Continuing, relay 18 includes a solenoid 46 which is energizable and de-energizable for respectively closing and opening pole 47 and contact 48, the pole being biased to the illustrated open position by the usual spring (not shown). Upon energization of relay 18, relay 16 is sequentially energized and re-energized, as previously explained. Upon de-energization of relay 18, no effect is had upon relay 16; however, following energization of relay 16 (poles 42 and 44 being closed against their respective contacts 43 and de-energization of relay 18 de-energizes solenoid 36 of relay 15, thereby opening the circuit for actuating mechanism 13 and simultaneously closing the circuit for actuating mechanism 14. On the other hand, following re-energization of relay 16 (poles 42 and 44 being in the open position as shown) de-cnergization of relay 18 has no effect on either of relays 15 and 16. Thus, even though relay 18 is de-energized during each open cycle of thermostat 11, as will be described more fully below, the former will de-energize relay 15 only during alternate open cycles following energization of relay 16.

V The final component in testing device 12 is rectifying control circuit 19 which includes variable auto transformer 49 connected across the potentials of source S, resistor 50 connected in series between transformer 49 and thermostat 11, full wave, selenium rectifier 51 connected in parallel with resistor 50, and condenser 52 connected in parallel between rectifier 51 and solenoid 46 of relay 18. As is apparent, circuit 19 is energized during each closed cycle of thermostat 11 to energize relay 18 and likewise de-energized during each open cycle to de-energize relay 18.

The purpose of using circuit 19 for testing thermostat 11 when assembled with pump 12 is twofold. First, autotransformer 49 is employed to boost the voltage slightly above the standard 120 volt supply from source S to provide the necessary voltage for operating rectifier 51 without varying the standard supply to pump 10. To this end, the voltage drop across resistor 50 equals the difference between the 120 volts from source S and the higher voltage provided by transformer 49. Thus, the current to pump 11 is not effected and no variations are introduced into the on and off cycles. Secondly, rectifier 51 is provided to supply intermittent direct current for energizing and de-energizing relay 18 in direct response to the closed and open cycles respectively of thermostat 1 1. Condenser 52 is provided to act as a filter for smoothing the output voltage so that the potential difference across the DC load of solenoid 46 is substantially constant, thereby insuring uniform energization and de-energization of relay 18 in accurate response to the closed and open cycles respectively of thermostat 1 1.

The operation of testing device 12 will now be described, first in testing thermostat 11, as a separate unit. Connection is made with source S and thermostat 11 through terminals T. Current is constantly supplied from input line 53 to continuously drive each of motors 20 and 20' as follows. The current flows through trunk line 54 and feeder line 55 to motor 20, returning by feeder line 56 and trunk line 57 to output line 58. At the same time, current flows to motor 20' through feeder line 59, returning via feeder line 60 and trunk line 57 to output line 58.

Assuming that thermostat 11 has just begun its closed cycle, current flows across terminals T through thermostat 11 and lines 61 and 62 to energize solenoid 40 of relay 16, returning through line 63 to output line 58. Upon energization of solenoid 40, cam 41 rotates to close poles 42 and 44 with their respective contacts 43 and 45.

At the same time, current tends to flow through the circuits for actuating each of mechanisms 13 and 14 as follows. For mechanism 13, current would flow through line 54, solenoid 24 to energize clutch 23, normally closed limit switch 30, line 64, and relay 15, returning to output line 58 via line 65. However, pole 37 and contact 39 of relay 15 are open to break this circuit. F or mechanism 14, current would flow through trunk line 66, solenoid 24 to actuate clutch 23, normally closed limit switch 30', line 67, closed pole 44 and contact 45 of relay 16, line 68, and closed pole 37 and contact 38 of relay 15, returning to output line 58 via line 65. This flow does not occur though, for the following reasons.

As soon as the circuit for actuating mechanism 14 is closed by relay 16, it is broken by relay 15. Simultaneously with the closing of pole 42 and contact 43 of relay 16, current flows from thermostat 11, through line 61, line 69 to energize solenoid 36 of relay 15, closed pole 42 and contact 43, returning to output line 58 via lines 70 and 63. Solenoid 36 immediately throws pole 37 of relay 15 from contact 38 to contact 39, thereby closing the circuit for actuating mechanism 13. As a consequence, solenoid 24 is energized to engage clutch 23 with differential 22, thereby rotating indicator 26 relative to dial 27 to measure the elapsed time of the closed cycle.

When the open cycle of thermostat 11 begins, the circuit across terminals T is broken, thereby de-energizing solenoid 40 of relay 16 and solenoid 36 of relay 15. However, relay 16 remains energized in that its poles and contacts stay closed. Upon de-energization of relay 15, pole 37 springs back to contact 38, thereby closing the circuit for actuating mechanism 14. Thus, solenoid 24 is energized to engage clutch 23' with differential 22 and rotate indicator 26' relative to dial 27' for measuring the elapsed time of the open cycle of relay 11. Simultaneously, the circuit for actuating mechanism 13 is broken by the open pole 37 and contact 39 of relay 15, thereby deenergizing solenoid 24 to disengage clutch 23 from differential 22 and stop rotation of indicator 26.

Inasmuch as the closed and open cycles of thermostat 11 follow each other in continuous sequence and are of very brief duration, measured in seconds, it would be extremely diflicult, if not impossible to record the measurements, unless testing device 12 were provided with some means for temporarily suspending its operation. Accordingly, following the first pair of closed and open cycles referred to above, mechanisms 13 and 14 remain deaactuated for the next succeeding pair of closed and open cycles to facilitate recording of their measurements.

As soon as the first open cycle is completed, thermostat 11 progresses to its next closed cycle, closing the circuit across terminals T so that the current flows through lines 61 and 62 to re-energize relay 16 as follows. Solenoid 40 is energized to rotate cam 41 to the position shown, thereby permitting poles 42 and 44 to spring open from their respective contacts 43 and 45. This action breaks the circuit for actuating mechanism 14 and prevents energization of solenoid 36 in relay 15. As thermostat 11 begins its next open cycle, the circuit across terminals T is again broken, but no elfect is produced upon the previously broken circuits for actuating mechanisms 13 and 14. Thus, the operator has ample time during this next pair of closed and open cycles to record the measurements taken by both mechanisms during the first pair of closed and open cycles, as well as to reset both indicators 26 and 26' by manually releasing brake 32. Upon completion of the second open cycle, thermostat 11 begins recycling to energize and re-energize relay 16 for further measurement taking and recording, respectively.

The operation of device 12 will now be described when employed to measure the closed and open cycles of thermostat 11 when assembled [with thermotic pump 10. Connection with source S is made between thermostat 11 and rectifying control circuit 19 instead of terminals T. While two sources S have been shown for simplicity of illustration, it is obvious that input line 53 and output line 58 could be carried up the upper source, rather than being terminated as shown. Thus, the two illustrated sources S are to be considered as one and the same.

In this type of installation, the two additional components of relay 18 and rectifying control circuit 19 are interposed between thermostat 11 and relay 16. However, the operation of relays 15 and 16, as well as mechanisms 13 and 14, are exactly the same as previously described and therefore need not be repeated in detail.

During each closed cycle of thermostat 11 and the corresponding on cycle of pump 10, current flows from upper source S through input line 71, transformer 49, resistor 50, line 72, thermostat 11, line 73 and pump 10, returning through line 74, thermostat 11, line 75 and output line 76. At the same time current flows through line 77, rectifier 51 and line 78 to join the current in line 72. As stated previously, the voltage drop across resistor 50 equals the additional voltage supplied by transformer 49, to avoid affecting the current drawn by thermostat 11 and pump 10 through line 72, thereby preventing any undesirable variations in the cycles of pump 10.

Rectifier 51 changes the incoming alternating current to direct current in the well-known manner, so that the DC. current flows through line 79 to energize solenoid 46 of relay 18 in direct response to the closed cycle of thermostat 11, returning via lines 80. Current also flows through filtering condenser 52 in the well known manner, whenever necessary to maintain the potential difference across the load of solenoid 46 substantially constant for accurate response of relay 18 to the cycles of thermostat 11. As is apparent, when thermostat 11 begins its open cycle, it shuts off pump 10, and de-energizes circuit 19 as well as relay 18.

Thus, when relay 18 is first energized, it energizes relay 16, which in turn energizes relay 15 for actuating mechanism 13, and when relay 18 is first de-energized, it de-ener gizes relay 15 for tie-actuating mechanism 13 and simultaneously actuating mechanism 14. Upon the next energization of relay 18, it re-energizes relay 16 which deactuates mechanism 14 and prevents actuation of mechanism 13, and upon the next de-energization of relay 18, no effect is had upon the previously de-actuated mechanism 13 and 14, whereby relay 18 only de-energizes relay 15 during alternate open cycles following energization of relay 16. As is now apparent, device 12 remains de-actuated for recording of the cycle measurements and resetting mechanisms 13 and 14 just as when used to test thermostat 11 as a separate unit.

During either of these two uses of device 12, it may be desirable to step relays 15 and 16 or relay 16 alone by means of manually operated, push button switch 17 For example, if the operator observes from movement of indicator 26' that thermostat 11 is on its open cycle, he realizes that the next closed cycle will re-energize relay 16 to de-actuate both mechanisms 13 and 14. To avoid waiting until the second following closed cycle before reading and recording the measurements, the operator can immediately de-actuate both mechanisms by depressing switch 17 to by-pass terminals T or relay 18 (whichever is being used) and step or re-energize relay 16. Thus, on the next closed cycle, relay 16 will be energized, thereby enabling the operator to immediately read and record the measurements. On the other hand, if the operator observes that both mechanisms are tie-actuated, he can depress switch 17 to determine which cycle is occurring. If it is the closed cycle, depression of switch 17 will energize or step both relays 15 and 16 to actuate mechanism 13, which actuation will be maintained by thermostat 11 for the duration of the cycle. If it is the open cycle, depression of switch 17 will energize or step both relays, but only relay 16 will remain energized, relay 15 being deenergized to actuate mechanism 14 upon release of switch 17.

In order to prevent damage to mechanism 13 or 14, while left unattended during operation, limit switches 30 and 30 are provided. Thus, when indicators 26 and 26 reach their limit of rotation, i.e., one complete revolution relative to their dials, lugs 29, and 29 engage and open limit switches 30 and 30' respectively, thereby breaking the circuits and de-actuating mechanisms 13 and 14 respectively. This frees the operator for other duties without requiring that device 12 be shut ofi to prevent damage to its measuring components. To reactuate mechanisms 13 and 14, the operator merely releases brake 32, permitting springs 31 and 31' to disengage lugs 29 and 29' from, and close limit switches 30 and 30, as well as to reset indicators 26 and 26'.

It will now be apparent how the invention accomplishes its objects in testing a time delay such as thermostat 11, either as a separate unit or when assembled with the apparatus it controls, such as intermittently operating thermotic pump Ill. Moreover, while only one embodiment of the invention has been described and illustrated herein, it is to be understood that various changes and modifications may be made therein by those skilled in the art, without departing from the spirit of the invention, the scope of which is to be determined by the appended claims.

Having thus described the invention, what is claimed and desired to be protected by Letters Patent is:

I. In combination with a time delay relay connected to a single source of electrical current, a device for testing the accuracy of said relay and comprising separate means connected to said source for measuring the elapsed times of said relays closed and open cycles respectively, first electrical control means connected to both of said measuring means and said relay, said first control means being energizable for actuating one of said measuring means and de-actuating the other of said measuring means and de-energiza ble by said relay in response to one of said cycles for actuating the other of said measuring means and de-actuating the one of said measuring means, and second electrical control means connected to the other of said measuring means, said first control means and relay, said second control means being energizable by said relay in response to another of said cycles for energizing said first control means and re-energizable by said relay in response to still another of said cycles for de-actuating the other of said measuring means and preventing energization of said first control means.

2. In the combination of claim 1, each of said measuring means comprising a motor-driven clock mechanism having clutch means operable by said first control means for actuating said mechanism, means for de-actuating said mechanism upon a predetermined amount of actuation thereof, means 'for resetting said mechanism and means for controlling the operation of said resetting means.

3. In combination with a time delay relay connected to a single source of electrical current, a device for testing the accuracy of said relay and comprising first and second means connected to said source for measuring the elapsed times of said relays closed and open cycles respectively, first electrical control means connected to said first and second measuring means and relay, said first control means being energizable for actuating said first measuring means and de-actuating said second measuring means and de-energizable by said relay in response to an open cycle for actuating said second measuring means and de-actuating said first measuring means, and second electrical control means connected to said second measuring means, first control means and relay, said second control means being energizable by said relay in response to a closed cycle for energizing said first control means and re-energizable by said relay in response to another closed cycles for de-actuating said second measuring means and preventing energization of said first control means.

4. In the combination of claim 3, each of said measuring means comprising a motor-driven clock mechanism having indicator means, clutch means energizable for actuating said indicator means, means for de-energizing said clutch means upon a predetermined amount of actuation of said indicator means, means for resetting said indicator means and means for controlling the operation of said resetting means, said first control means comprising relay means for energizing said clutch means, and said second control means comprising relay means.

5. In combination with a recycling thermal time delay relay connected to a Single source of electrical current, a device for testing the accuracy of said thermal relay and comprising first and second clock mechanisms connected to said source for indicating the elapsed times of said thermal relays closed and open cycles respectively, first relay means connected to said first and second clock mechanisms and thermal relay, said first relay means being energizable for actuating said first clock mechanism and de-actuating said second clock mechanism and de-energizable by said thermal relay in response to an open cycle for actuating said second clock mechanism and de-actuating said first clock mechanism, and second relay means connected to said second clock mechanism, first relay means and thermal relay, said second relay means being energizable by said thermal relay in response to a closed cycle for energizing said first relay means and re-energizable by said thermal relay in response to another closed cycle for de-actuating said second clock mechanism and preventing energization of said first relay means.

6. In the combination of claim 5, each of said clock mechanisms comprising a motor connected to said source, diflerential means driven by said motor, indicator means actuatable by said differential means, clutch means energizabe for engagement with said differential means to actuate said indicator means, switch means engageable with said indicator means for de-energizing said clutch means upon a predetermined amount of actuation of said indicator means, self-actuating means connected to said indicator means for resetting the same, and brake means disengageable from said indicator means for permitting actuation of said resetting means, said first relay means being of the single pole, double throw type for energizing said clutch means, and said second relay means being of the double pole, single throw type.

7. In combination with a time delay relay connected to a single source of electrical current, a device for testing the accuracy of said relay and comprising first and second means for measuring the elapsed times of said relays closed and open cycles respectively, first and second circuits connected to said source, said first circuit for actuating and de-actuating said first measuring means and said second circuit for actuating and de-actuating said second measuring means, first electrical control means connected to said circuits and relay, said first control means being energizable for closing said first circuit and opening said second circuit and being de-energizable by said relay in response to an open cycle for opening said first circuit and closing said second circuit, and second electrical control means connected to said second circuit, first control means and relay, said second control means being energizable by said relay in response to one closed cycle for closing said second circuit and energizing said first control means and re-energizable by said relay in response to another closed cycle for opening said second circuit and preventing energization of said first control means.

8. In the combination of claim 7, each of said measuring means comprising a motor-driven clock mechanism having movable indicator means, magnetic clutch means energizable for moving and de-energizable for stopping said indicator means, switch means for de-energizing said clutch means upon a predetermined amount of movement of said indicator means, self-actuating means for resetting said indicator means, and manually releasable brake meansfor permitting actuation of said resetting means, said first control means comprising magnetic relay 9 a means for sequentiallyjenergizing and tie-energizing each of said clutch means, and said second control means comprising magnetic relay means.

9. In combination With a re-cycling thermal time delay relay connected to a single source of electrical current, a device for testing the accuracy of said thermal relay and comprising first and second clock mechanisms for measuring the elapsed times of said thermal relays closed and open cycles respectively, first and second circuits connected to said source, said first circuit for actuating and deactuating said first clock mechanism and said second circuit for actuating and deactuating said second clock mechanism, a first magnetic relay connected to said circuits and thermal relay, said first relay being energizable for simultaneously closing said first circuit and opening said second circuit and being de-energizable by said thermal relay in response to an open cycle for simultaneously opening said first circuit and closing said second circuit, a second magnetic relay connected to said second circuit, first and thermal relays, said second relay being energizable by said thermal relay in response to one closed cycle for simultaneously closing said second circuit and energizing said first relay and re-energizable by said thermal relay in response to the next closed cycle for opening said second circuit and preventing energization of said first relay, and manually operable means connected between said second and thermal relays for energizing and re-energizing said second relay independently of said thermal relay.

10. In the combination of claim 9, each of said clockmechanisms comprising a dial, a synchronous motor connected to said source, diiferential means driven by said motor, indicator means rotatable relative to said dial by said differential means, a magnetic clutch energizable for engagement with said dififerential means to rotate said indicator means and de-energizable for disengagement from said differential means to stop said indicator means, a limit switch engageable with said indicator means for de-energizing said magnetic clutch upon a predetermined amount of rotation of said indicator means, self-actuating resilient means connected to said indicator means for resetting the same by reversing its direction of rotation, and a manually releasable brake simultaneously disengageable from each indicator means for permitting actuation of each resetting means, said first relay being of the single pole, double throw type for sequentially energizing and deenergizing each magnetic clutch, said second relay being of the double pole, single throw type, and said manually operable means comprising a normally open, push button switch; I

11. In combination with a time delay relay connected to a single source of electrical current a device for testing the accuracy of said relay and comprising first and second means for measuring the elapsed times of said relays closed and open cycles respectively, first and second circuits connected to said source, said first circuit for actuating and de-actuating said first measuring means and said second circuit for actuating and de-actuating said second measuring means, first control means connected to said first circuit, said first control means being energizable for closing said first circuit and opening said second circuit and de-energizable for opening said first circuit and closing said second circuit, second control means connected to said second circuit and first control means, said second control means being energizable for closing said second circuit and energizing said first control means and re-energizable for opening said second circuit and preventing energization of said first control means, and third control means connected to said first and second control means and relay, said third control means being energizable by said relay in response to each closed cycle for sequentially energizing and re-energizing said second control means and de-energizable by said relay in response to each open cycle for de-energizing said first control means during alternate open cycles.

12. In the combination of claim 11, each of said measuring means comprising a motor-driven clock mechanism having clutch means energiza-ble for actuating and deenergizable for tie-actuating said mechanism, means for de-energizing said clutch means upon a predetermined amount of actuation of said mechanism, means for re setting said mecahnism, and means for controlling the operation of said resetting means, said first control means comprising relay means for energizing and de-energizing said clutch means, and said second and third control means comprising relay means.

13. In combination with an intermittently operating pump controlled by a recycling thermal time delay relay assembled therewith and connected to a single source of electrical current, a device for testing the accuracy of said thermal relay and comprising first and second clock mechanisms for measuring the elapsed times of said thermal relays closed and open cycles respectively, first and second circuits connected to said source, said first circuit for actuating and de-actuating said first clock mechanism and said second circuit for actuating and de-actuating said second clock mechanism, first relay means connected to said circuits, said first relay means being energizable for closing said first circuit and opening said second circuit, and de-energizable for opening said first circuit and closing said second circuit, second relay means connected to said second circuit and first relay means, said second relay means being energizable for closing said second circuit and energizing said first relay means and reenergizable for opening said second circuit and preventing energization of said first relay means, and third relay means connected to said first and second relay means and said thermal relay, said third relay means being energizable by said thermal relay in response to each closed cycle for sequentially energizing and re-energizing said second relay means and de-energizable by said thermal relay in response to each open cycle for de-energizing said first relay means during alternate open cycles.

14. In the combination of claim 13, each of said clock mechanisms comprising a motor connected to said source, differential means driven by said motor, indicator means movable by said differential means, magnetic clutch means energizable for engagement with said difierential means to move said indicator means and de-energizable for disengagement from said differential means to stop said indicator means, switch means engageable with said indicator means for tie-energizing said clutch means upon a predetermined amount of movement of said indicator means, self-actuating means connected to said indicator means for resetting the same, and brake means disengageable from said indicator means for permitting actuation of said resetting means, said first relay means being of the single pole, double throw type for energizing and de-energizing said clutch means, said second relay means being of the double pole, single throw type, and said third relay means being of the single pole, single throw type.

15. In combination with a time delay relay connected to a single source of electrical current, a device for testing the accuracy of said relay and comprising first and second means for measuring :the elapsed times of said relays closed and open cycles respectively, first and second circuits connected to said source, said first circuit for actuating and de-actuating said first measuring means and said second circuit for actuating and de-actuating said second measuring means, first control means connected to said circuits, said first control means being energizable for closing said first circuit and opening said second circuit and de-energizable for opening said first circuit and closing said second circuit, second control means connected to said second circuit and first control means, said second control means being energiza'ble for closing said second circuit and energizing said first control means and re energizable for opening said second circuit and preventing energization of said first control means, third control means connected to said first and second control means, said third control means being energizable for sequentially energizing and re-energiz-ing said second control means and de-energizable for tie-energizing said first control means during alternate open cycles, and fourth control means connected to said source, third control means and relay, said fourth control means being both energizable and de-energizable by said relay in response to each closed and open cycle respectively, for sequentially energizing and de-energizing said third control mean-s.

16. In the combination of claim 15, each of said measuring means comprising a motor-driven clock mechanism having movable indicator means, magnetic clutch means energiz'able and de-energizable for moving and stopping said indicator means, switch means for de-energizing said clutch means upon a predetermined amonut of movement of said indicator means, self-actuating means for resetting said indicator means, and manually releasable brake means for permitting actuation of said resetting means, said first control means comprising magnetic relay means for sequentially energizing and deenergizing each clutch means, said second and third control means comprising magnetic relay means, and said fourth control means comprising rectifying circuit means.

17. In combination with an intermittently operating pump controlled by a recycling thermal time delay relay assembled therewith and connected to a single source of alternating current, a device for testing the accuracy of said thermal relay and comprising first and second clock mechanisms for measuring the elapsed times of said thermal relays closed and open cycles respectively, first and second circuit-s connected to said source, said first circuit for actuating and de actuating said first clock mechanism and said second circuit for actuating and deactuating said second clock mechanism, a first magnetic relay connected to said circuits, said first relay being energiztable for simultaneously closing said first circuit and opening said second circuit and de-energizable for simultaneously opening said first circuit and closing said second circuit, a second magnetic relay connected to said second circuit and first relay, said second relay being energiza'ble for simultaneously closing said second circuit and energizing said first relay and re-energizable for simultaneously opening said second circuit and preventing energization of said first relay, a third magnetic relay connected to said first and second relays, said third relay being energizable for sequentially energizing and reenergizing said second relay and de-energizable for de energizing said first relay during alternate open cycles, a rectifying control circuit connected to said source and said third and thermal relays, said "control circuit being both energizable and de-energizab-le by said thermal relay in response to each closed and open cycle respectively for supplying intermittent direct current to sequentially energize and de-energize said third relay, and manually operable means connected between said second and third relays for energizing and re-energizing said second relay independently of said third relay.

18. In the combination of-claim 17, each of said clock mechanisms comprising a synchronous motor connected to said source, difierential means driven by said motor, indicator means rotatable by said differential means, a magnetic clutch energiza ble for engagement with said differential means to rotate said indicator means in one direction and de-energizable for disengagement from said differential means to stop said indicator means, a limit switch engageable with said indicator means for deenergizing said clutch upon a predetermined amount of rotation of said indicator means, self-actuated resilient means connected to said indicator means for resetting the same by reversing its direction of rotation, and a manually releasable brake simultaneously disengageable from each indicator means for permitting actuation of said resetting means, said first relay being of the single pole, double throw type for sequentially energizing and deenergizing each of said clutches, said second relay being of the double pole, single throw type, said third relay being of the single pole, single throw type, said rectifying control circuit including an auto transformer connected to said alternating current source, a resistor connected in series between said transformer and thermal relay, a full Wave rectifier connected in parallel with said resistance, and a condenser connected in parallel between said rectifier and third relay, and said manually operable means comprising a normally open, push button switch.

References Cited by the Examiner UNITED STATES PATENTS 2,498,669 2/1950 From 178-l75.2 2,828,465 3/1958 Morton 324-28 2,877,405 3/ 1959 Morton 32428 FOREIGN PATENTS 584,311 1/1947 Great Britain.

WALTER L. CARLSO'N, Primary Examiner.

SAMUEL BERNSTEIN, FREDERICK M. STRADER,

Examiners.

G. R. STRECKER, Assistant Examiner. 

1. IN COMBINATION WITH A TIME DELAY RELAY CONNECTED TO A SINGLE SOURCE OF ELECTRICAL CURRENT, A DEVICE FOR TESTING THE ACCURACY OF SAID RELAY AND COMPRISING SEPARATE MEANS CONNECTED TO SAID SOURCE FOR MEASURING THE ELAPSED TIMES OF SAID RELAY''S CLOSED AND OPEN CYCLES RESPECTIVELY FIRST ELECTRICAL CONTROL MEANS CONNECTED TO BOTH OF SAID MEASURING MEANS AND SAID RELAY, SAID FIRST CONTROL MEANS BEING ENERGIZABLE FOR ACTUATING ONE OF SAID MEASURING MEANS AND DE-ACTUATING THE OTHER OF SAID MEASURING MEANS AND DE-ENERGIZABLE BY SAID RELAY IN RESPONSE TO ONE OF SAID CYCLES FOR ACTUATING THE OTHER OF SAID MEASURING MEANS AND DE-ACTUATING THE ONE OF SAID MEASURING MEANS, AND SECOND ELECTRICAL CONTROL MEANS CONNECTED TO THE OTHER OF SAID MEASURING MEANS, SAID FIRST CONTROL MEANS AND RELAY, SAID SECOND CONTROL MEANS BEING ENERGIZABLE BY SAID RELAY IN RESPONSE TO ANOTHER OF SAID CYCLES FOR ENERGIZING SAID FIRST CONTROL MEANS AND RE-ENERGIZABLE BY 